I. This invention relates to demulsifying mixtures of oil and water and in particular demulsification of tramp oils in cutting fluid oils and greases in commercial laundry effluent.
II. Description of the Art Practices
In the past, little care was given to effluent waste streams. The consequences of ignoring waste streams lead not only to environmental catastrophe, but also to the loss of valuable resources which could be reclaimed from the effluent stream. In particular, it has become apparent that greases and oils from waste streams may be recovered and sold for industrial purposes. Alternatively, certain oils may be recycled into the process from which they were originally effluted.
It has recently become important, particularly to commercial laundries, that effluent treatment must be accomplished to meet rigid Environmental Protection Agency Standards in the United States. Of course, regulations either exist or are being promulgated in several foreign countries dealing with waste treatment. The current standards for removal of grease and oils from waste water require that a commercial laundry discharge no more than 250 ppm of oils and grease to sewage treatment facilities. While large commercial laundries are capable of meeting the requirements through their greater economic advantage, smaller laundries are indeed suffering in attempting to comply with the rigid standards. It is thus an aspect of the present invention to deal with small commercial laundries and to provide an effective method for meeting EPA grease and oil discharge limits.
It is known from U.S. Pat. No. 4,104,164 issued Aug. 1, 1978 to Chelton, that a system for recovery of large particulate matter may be accomplished through centrifugal separation. The Chelton patent does not deal with any particular chemical means for enhancing the separation of oils and grease from the waste water. U.S. Pat. No. 4,546,511 issued to Kaufmann on Oct. 15, 1985, describes a continuous flow laundry system incorporating a method of fluid flow control. The Kaufmann system requires many tank sand recirculates effluent water to transfer heat to fresh water.
U.S. Pat. No. 4,797,214, issued Jan. 10, 1989, to Sevier, describes a process for treating an emulsion or solution of water and oil by contacting the same with an inorganic salt and a polyelectrolyte flocculant. The Sevier patent describes chemical means which eventually contaminates the water employed with a salt such as sodium chloride and further uses as a demulsifying agent, sulfuric acid. It can be seen that the Sevier method of demulsification has certain inherent difficulties. Meffertet et al, in U.S. Pat. No. 4,773,939, issued Sep. 27, 1988, describes a process of regenerating a soil-laden detergent solution comprising contacting the solution with a soil collector utilizing a polyfunctional quaternary ammonium compound. The difficulty in utilizing any quaternary compound is that any of the material which is discharged is deleterious to bacteria utilized in sewage treatment processes.
U.S. Pat. No. 4,846,976 issued Jul. 11, 1989 to Ford describes a filtration system for treating an emulsion containing water, an oil or a fat, an emulsifying agent and insoluble solid materials such as are present from a maritime oil emulsion containing an anionic detergent and solid greasy calcium salt of the detergent. The Ford patent describes a mechanical means utilizing microfilters for separating the oil or fat from the solid-free emulsion.
A sludge and slime separating and settling device are described in U.S. Pat. No. 4,132,643 issued Jan. 2, 1979 to Hellqvist. The Hellqvist patent states that sludge and slime may be separated from various waste-water sources from laundries, industrial, agricultural, or other sources.
U.S. Pat. No. 4,427,409 issued Jan. 24, 1984 to Gregorian et al describes effluent streams obtained from desizing, scouring and/or bleaching or mercerizing textile fabrics. Various surfactants are described by Gregorian et al for use in the process described there in. Gregorian et al makes further disclosures of compositions for treating textiles in U.S. Pat. Nos. 4,118,526 and 4,347,145 which were issued respectively on Jun. 6, 1975, and Aug. 31, 1982.
U.S. Pat. No. 4,420,578 issued Dec. 13, 1983 to Hagens et al describes methods for cleaning beverage bottles through the use of siloxane compositions. The glass bottle recycling industry generates tremendous volumes of industrial waste containing various organic components including greases. Weinberger in U.S. Pat. No. 4,390,466 issued Jun. 28, 1983 describes various aqueous liquid detergents useful for laundering compositions. Various nonionic surfactants are described in U.S. Pat. No. 4,391,719 issued to Meister on Jul. 5, 1983.
Lancz in U.S. Pat. No. 4,784,788 issued Nov. 15, 1988 describes hard surface viscous cleaning compositions containing various solvents and nonionic surfactants which form a nonflowable gelled composition. The compositions of Lancz also contain water soluble particulate builder-abrasive materials. Wixon in U.S. Pat. No. 4,790,856,issued Dec. 13, 1988 describes nonionic surfactant-cationic fabric softener/anti-static agents containing sulfosuccinamate.
Various iminodipropionate compounds are described in an Industrial Product Directory labeled 12-1282. Similar disclosures are made in an document entitled "Cospha/CD" dated Dec. 18, 1986. A further disclosure of dipropionates is found in a bulletin of Alkaril Chemicals, Inc. bulletin 1028-255 A February 1987. Further disclosures of amphoteric materials are made in a brochure entitled "Properties and Formulations of Deriphat Amphoteric Surfactants" pages 1-37.
Disclosures of Alkyl dipropionates are made in DeForest Enterprises, Inc. bulletin Number 720 REV.2/89. Certain nonionic surfactants are described in bulletin number 110 of DeForest Enterprises, Inc., entitled "DeIONIC LF-EP-16." REV. 12/87. A further disclosure of polyalkoxylated surfactants is found in DeForest Enterprises, Inc. bulletin Number 109, entitled DeIonic LT-EP15, dated 11/89. Further disclosures of amphoteric surfactants are found in DeForest Enterprises, Inc. bulletin 1350, dated 12/89 and entitled "Surfactant AN 5080 S-DF".
The various publications described above disclose the problem of treating waste water effectively to remove fats, organic material, paint pigments, and greases. Yet none of the references taken singly teach the effective method found here in in rapidly demulsifying effluent obtained from sources such as tramp oils or commercial laundries.
U.S. Pat. No. 4,202,795, issued May 13, 1980 to Burnham, et al teaches methods and additives for bringing about the delayed release of a chemical such as a gel breaker or a demulsifier in an aqueous fluid. U.S. Pat. No. 4,734,205 issued Mar. 29, 1988 to Jacques, et al teaches a process stated to be useful for breaking or resolving oil-in-water emulsions, such as those produced during oil recovery operations.
Jacques et al in U.S. Pat. No. 4,202,795 issued Mar. 29, 1988 discloses breaking oil in water emulsions. In U.S. Pat. No. 4,741,835 issued May 3, 1988 to Jacques further discussion of the treatment of waste water with acrylamides.
Spei et al, in U.S. Pat. No. 4,961,858 issued Oct. 9, 1990 teaches demulsifying processes using polyamines. U.S. Pat. No. 4,877,842 issued Oct. 31, 1989 to Burkis et al teaches the reaction products of polyoxyalkylene amines and vinyl monomers for use in breaking emulsions.
Gutierrez et al in U.S. Pat. No. 4,857,217 issued Aug. 15, 1989 discloses amide containing dispersants. A further publication of Gutierrez et al issued as U.S. Pat. No. 4,963,275 on Oct. 16, 1990 teaches amide containing dispersants. Yet another publication of Gutierrez et al issued as U.S. Pat. No. 4,956,107 on Sep. 11, 1990 discloses amide containing dispersants. Suzuki et al in U.S. Pat. No. 4,182,690 issued Jan. 8, 1980, discloses a method of breaking emulsions using a combination of a hydrophobic and hydrophillic components.
In U.S. Pat. No. 4,120,815, issued Oct. 17, 1978 to Raman, there is disclosed diallyl dimethyl ammonium chloride emulsion polymers to break emulsions. Starch in U.S. Pat. No. 4,978,471 issued Dec. 18, 1990 teaches antifoams useful in handling emulsions. Starch's U.S. Pat. No. 4,983,316 issued Jan. 8, 1991 also discloses antifoams useful in handling emulsions.
The present invention deals with an effective composition which will demulsify effluent containing grease and oils. It is also desired to obtain a demulsifying system which does not lessen the cleaning benefits and which may be utilized to enhance cleaning.
Furthermore, it is desirable to have a chemical system for demulsification which may be added either to the wash liquor or which may be used to treat a tank of effluent to bring about rapid demulsification.
Throughout the specific and claims, percentages and ratios are by weight, temperatures are given in degrees Celsius and pressures are given in KPa gauge unless otherwise indicated. To the extent that any references cited here in are applicable to the present invention, they are here by specifically incorporated by reference.